Study On Ultraviolet And X-ray Variability Properties Of Blazars With Swift Observations

Since Swift satellite was launched in 2005,it has accumulated a large number of quasi-simultaneous X-ray and ultraviolet band observation data.93 blazars with good observation quality were selected for data processing.We choosed 35 blazars which had been observed more than 20 times for further research.First of all,we analysed hardness ratio of 7 blazars.Variations of hardness were different in different states.We believe it is the result of different emission dominance mechanism.After that,we calculated broad band spectral index (?_ox)of the 35 blazars.The results showed that there was a correlation between ?_oxand luminosity.And the correlation laws of different types of blazars were different.Our calculation results of the F_varare consistent with ?_ox'results.When the flux variability in ultraviolet-band are stronger,the ?_oxis linearly correlated with L_2500?.When the flux variability in the X-ray are stronger,the ?_oxis linearly correlated with L_2keV.In order to determine whether X-ray and ultraviolet band are really uncorrelated,we calculated Discrete correlation function?DCF?.We found no correlation.For ?_ox's result,we think it is caused by ultraviolet and X-ray's position in Spectral Energy Distribution?SED?.In general,the fluctuation of the band in the SED descending phase is more drastic than that in the ascending phase.This reflects that the emission dominant mechanisms of different types blazars are different.And the relative intensity of the X-ray and ultraviolet band's emission influences the linear trend of the ?_ox.